TW201415740A - Composition for filling discharge gap and electrostatic discharge protector - Google Patents

Abstract

To provide an electrostatic discharge (ESD) protector which can take an arbitrary shape and serve as an easy ESD countermeasures for circuit boards with various designs or other various electronic devices, and which exhibits excellent operating properties at discharging even in a case where the discharge gap is wide, and which enables downsizing and cost reduction; and to provide a composition for filling a discharge gap, said composition being usable in producing the ESD protector. This composition for filling a discharge gap is characterized in that: the composition comprises a metal powder (A1), an aluminum powder (A2) and a binder component (B); the surfaces of the metal primary particles constituting the metal powder (A1) are at least partially covered with a film made of a metal alkoxide hydrolyzate; and the surfaces of the aluminum primary particles constituting the aluminum powder (A2) are not covered with a film made of a metal alkoxide hydrolyzate.

Description

Discharge gap filling composition and electrostatic discharge protector

The present invention relates to a discharge gap filling composition and an electrostatic discharge protector, and more particularly to an electrostatic discharge protector which is excellent in actuation during discharge, can be reduced in size and cost, and is used for electrostatic discharge. A composition for filling the discharge gap of the protective body.

If a charged conductive object (such as a human body) comes into contact with other conductive objects (such as electronic devices), or is in close proximity, a severe discharge will occur. This phenomenon is called electro-static discharge (hereinafter also referred to as "ESD"), and causes problems such as malfunction or damage of an electronic device, or causes an explosion in an explosive environment.

ESD is one of the destructive and inevitable phenomena that electrical systems and integrated circuits can suffer. From the electrical point of view, ESD refers to a transitional high current phenomenon in which a high current having a peak current of several amps lasts for 10 n seconds to 300 n seconds. Therefore, when ESD occurs, if approximately a few amps of current is not conducted to the outside of the integrated circuit within tens of n seconds, the integrated circuit may be damaged by difficulty, or may be defective or inferior. And become unable to function properly.

In recent years, the trend of weight reduction, thinning, and miniaturization of electronic components and electronic devices has rapidly progressed. Along with this, the degree of integration of the semiconductor or the mounting density of the electronic component of the printed wiring board is remarkably increased, and the integrated electronic component or the signal line is extremely close to each other. In addition, the signal processing speed is also speeded up. As a result, high-frequency radiation noise is caused to be easily triggered. Based on such a situation, development of an electrostatic discharge protection element having an IC or the like in a protection circuit to avoid ESD damage is performed.

In the past, an electrostatic discharge protection element that protects an IC or the like in an IC to prevent ESD damage is an element having a bulk structure composed of a sintered body such as a metal oxide (see, for example, Patent Document 1). This device is a laminated wafer varistor composed of a sintered body, and is provided with a laminate and a pair of external electrodes. The varistor has a property that a current that does not flow therethrough rapidly flows out when a voltage is applied to a certain value or more, and has an excellent suppressing force against electrostatic discharge. However, the laminated wafer varistor of the sintered body cannot avoid complicated manufacturing processes caused by sheet molding, internal electrode printing, sheet lamination, etc., and has defects such as interlayer peeling easily occurring in the mounting step. problem.

Other electrostatic discharge protection elements, such as ICs in a protection circuit to avoid ESD damage, are discharge type elements. The discharge type component has a small leakage current and is simple in principle, and has the advantage of being difficult to malfunction. In addition, the discharge voltage can be adjusted by the width of the discharge gap. Moreover, when the sealing structure is formed, it is determined according to the pressure of the gas and the type of the gas. The width of the gap. As a discharge type element which is actually sold, a cylindrical ceramic surface conductor film is formed, and a discharge gap is provided in the film by laser or the like, and this is sealed by a glass. This commercially available glass-sealed discharge type element is excellent in electrostatic discharge protection characteristics, but its shape is complicated, so that it is limited in size as a small surface mount element, and it is difficult to reduce the cost. problem.

Further, a method of directly forming the discharge gap wiring on the wiring and adjusting the discharge voltage by the width of the discharge gap is disclosed (for example, refer to Patent Documents 2 to 4). Patent Document 2 exemplifies that the width of the discharge gap is 4 mm, and Patent Document 3 exemplifies that the width of the discharge gap is 0.15 mm. Further, Patent Document 4 discloses that, in order to protect an electronic component, a discharge gap is preferably 5 to 60 μm, and in order to protect an IC or an LSI sensitive to electrostatic discharge, a discharge gap is set to 1 to 30 μm. Preferably, it can be increased to about 150 μm particularly in applications where only a large pulse voltage portion is removed.

However, if the discharge gap portion is not protected, the gas discharge may be caused by application of a high voltage, or the discharge voltage may be changed due to contamination of the surface of the conductor due to humidity or gas in the environment, or carbonization of the substrate provided with the electrode. There is a possibility of short circuiting of the electrodes.

Further, in an electrostatic discharge protector having a discharge gap, a general operating voltage, for example, when a direct current (DC) is less than 10 V, an insulating member having a withstand voltage is required because of high insulation resistance. It is effective to set the discharge gap of the electrode couple. If the discharge gap is to be protected, it is generally used as a resisting agent for the insulating member. Filling the discharge gap causes a large increase in the discharge voltage, which is not practical. When a general resist is filled in a very narrow discharge gap of about 1 to 2 μm or less, the discharge voltage can be lowered, but the resisting agent can be slightly deteriorated or the insulation resistance can be lowered, or depending on the situation. There are different issues that can be turned on.

Patent Document 5 discloses a protective element in which a discharge gap of 10 to 50 μm is provided on an insulating substrate, and a pair of electrode patterns having opposite ends is provided with ZnO as a main component and carbonization. A functional membrane of cockroaches. This protective element has a simple structure as compared with a laminated wafer varistor, and has an advantage that it can be manufactured as a thick film element on a substrate.

However, these ESD countermeasure elements are required to reduce the mounting area in accordance with the evolution of electronic devices. However, since the form is an element after all, it needs to be mounted on the wiring board by solder or the like. Therefore, in an electronic device, the degree of freedom in design is reduced, and the height is included and the limit is small.

Therefore, it is desirable to take ESD measures not only to fix the components, but also to include the free form of miniaturization, the necessary parts, and the necessary area.

On the other hand, the use of a resin composition as an ESD protection material has been disclosed (for example, refer to Patent Document 6). The resin composition is characterized by comprising conductive particles having a base material composed of a mixture of insulating binders and having an average particle diameter of less than 10 μm, and semiconductor particles having an average particle diameter of less than 10 μm.

Further, it is disclosed that a constituent material of a mixture of conductivity and semiconductor particles having a surface covered with an insulating oxide film, a composition material having a specific particle diameter range, and a conductive particle are formed by an insulating binder. The surface spacer is made of a specific composition material or the like as an ESD protection material (for example, refer to Patent Document 7).

However, in the method described in Patent Document 7, since the method of dispersing the conductive particles or the semiconductor particles is not optimized, a high electric resistance value cannot be obtained at a low voltage, or a low electric power cannot be obtained at a high voltage. There are technical instability factors such as impedance values.

Further, these compositions are not suitable for the purpose of protecting a low-resistance integrated circuit because of the high operating voltage during discharge. In particular, when a large amount of semiconductive particles or insulating particles are blended, the operability is lowered. On the other hand, in the case of only metal particles, there is a problem that the withstand voltage is low.

In order to solve the above problems, it has been disclosed that a discharge gap is filled with a composition containing a compound containing a metal oxide-coated metal powder and a binder (for example, refer to Patent Document 8). However, the above-described composition is assumed to have a discharge gap of, for example, about 300 μm or less. If even a wider discharge gap can be applied, the degree of freedom in wiring design can be significantly improved.

If the composition is filled with a large amount of a metal powder in which a wide discharge gap is coated with the metal oxide, the electrostatic discharge performance is stabilized in order to achieve good operability in a wider discharge gap. The tendency to decrease. In addition, if only conductive particles are blended When the composition of the sub-package is filled with a wider discharge gap, the withstand voltage tends to be lowered.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2005-353845

[Patent Document 2] Japanese Patent Laid-Open No. Hei 3-89588

[Patent Document 3] Japanese Patent Laid-Open No. Hei 5-67851

[Patent Document 4] Japanese Patent Laid-Open No. 10-27668

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2007-266479

[Patent Document 6] Japanese Patent Publication No. 2001-523040

[Patent Document 7] U.S. Patent No. 4,726,991

[Patent Document 8] International Publication No. 2010/147095

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electronic device such as an electronic circuit board of various designs, which can easily and easily achieve ESD countermeasures, and even in a wide discharge gap. It is also excellent in the operability at the time of discharge, an electrostatic discharge protector which can be reduced in size and cost, and a discharge gap filling composition which can be used for the manufacture of such an electrostatic discharge protector.

The present invention relates to, for example, the following [1] to [19].

[1] A discharge gap filling composition comprising a metal powder (A1), an aluminum powder (A2), and a binder component (B), wherein the metal powder (A1) is a surface of a primary particle of a metal At least a part of the film is composed of a film composed of a hydrolyzed product of a metal alkoxide, and the surface of the aluminum powder (A2)-based primary particles of aluminum is not covered by a film composed of a hydrolyzed product of a metal alkoxide. By.

[2] The composition for discharge gap filling according to [1], wherein the shape of the primary particles of the metal of the metal powder (A1) and the shape of the primary particles of the aluminum powder (A2) are in the form of flakes.

[3] The composition for discharge gap filling according to [1] or [2], wherein the average particle diameter of the primary particles of the metal of the metal powder (A1) is 1 to 15 μm, and the average of the primary particles of the aluminum powder (A2) The particle size is 5 to 70 μm.

[4] The discharge gap filling composition according to any one of [1] to [3] wherein the metal element of the metal powder (A1) is manganese, cerium, zirconium, hafnium, tantalum, molybdenum or vanadium. At least one selected from the group consisting of nickel, cobalt, chromium, magnesium, titanium or aluminum.

[5] The discharge gap filling composition according to any one of [1] to [4] wherein the metal element of the metal of the metal powder (A1) is aluminum.

[6] The discharge gap filling composition according to any one of [1] to [5] wherein the mass ratio of the metal powder (A1) to the aluminum powder (A2) in the discharge gap filling composition is 98:2 ~20:80.

[7] The discharge gap filling composition according to any one of [1] to [6] wherein the metal alkoxide is represented by the following general formula (1).

(In the formula (1), M is a metal atom, O is an oxygen atom, R is each independently an alkyl group having 1 to 20 carbon atoms, and n is an integer of 1 to 40).

[8] The discharge gap filling composition according to [7], wherein M in the above general formula (1) is ruthenium, titanium, zirconium, hafnium or tantalum.

[9] The discharge gap filling composition according to any one of [1] to [8] wherein the surface of the primary particles of the metal of the metal powder (A1) and/or the aluminum powder (A2) is auto-oxidized. membrane.

[10] The composition for discharge gap filling according to any one of [1] to [9] wherein the binder component (B) contains a thermosetting compound or an active energy ray-curable compound.

[11] The composition for discharge gap filling according to [10], wherein the binder component (B) contains a thermosetting urethane resin.

[12] The discharge gap filling composition according to any one of [1] to [11] wherein the total content of the metal powder (A1) and the metal powder (A2) in the solid content of the discharge gap filling composition is It is 3 to 95% by mass, and the content of the binder (B) is 5 to 97% by mass.

[13] An electrostatic discharge protector having at least two electrodes, The electrostatic discharge protector of the discharge gap between the two electrodes is characterized in that the discharge gap filling composition according to any one of [1] to [12] is filled in the discharge gap. Gap filling member.

[14] The electrostatic discharge protector according to [13], wherein the discharge gap has a width of 300 μm or more and 1 mm or less.

[15] The electrostatic discharge protector of [13] or [14], wherein a protective layer is formed on a surface of the discharge gap filling member.

[16] An electronic circuit board comprising the electrostatic discharge protector according to any one of [13] to [15].

[17] A flexible electronic circuit board having the electrostatic discharge protector according to any one of [13] to [15].

[18] An IC chip mounting substrate, comprising the electrostatic discharge protector according to any one of [13] to [15].

[19] An electronic device comprising the electronic circuit board of [16], the flexible electronic circuit board of [17], or the IC wafer mounting substrate of [18].

When the composition for discharge gap filling of the present invention is used, it is possible to manufacture a small-sized electrostatic discharge protector which is low in cost and excellent in operability at the time of discharge even in a wide discharge gap, and can easily realize electrostatic discharge protection.

Further, when the discharge gap filling composition of the present invention is used, it is possible to adjust by setting the width of the discharge gap to a specific interval. Since the voltage is applied, an electrostatic discharge protector excellent in adjustment accuracy of the actuation voltage can be obtained.

According to the present invention, even if the width of the discharge gap is, for example, a wide width exceeding 300 μm, the resistance value at the time of electrostatic discharge is lowered, and the insulation property can be restored after the voltage is released. Therefore, it is not necessary to process the discharge gap provided with the discharge gap filling member obtained by hardening the discharge gap filling composition to be particularly narrow, and generally, for example, a space of a varistor element or the like is welded, for example, 0.5 mm or 1.0 mm. The discharge gap can also be applied.

In the electrostatic discharge protector of the present invention, a discharge gap corresponding to a required operating voltage is formed between the electrodes, and the discharge gap filling composition is filled in the discharge gap to be cured or cured. It can be formed in a free shape and easily. Therefore, the electrostatic discharge protection system of the present invention can be applied to an IC chip mounting substrate incorporated in a digital device such as a mobile phone or a mobile device in which a hand touches a large amount of hands and is easily stored in static electricity, and more specifically In other words, it can be applied to a smart card or a representative such as a ball grid array (BGA), a chip size package (CSP), a chip on board (COB), or the like. IC card for the wafer card.

11‧‧‧: Electrostatic discharge protection

12A‧‧‧electrode

12B‧‧‧electrode

13‧‧‧Discharge gap filling member

14‧‧‧discharge gap

21‧‧‧Electrostatic discharge protection

22A‧‧‧electrode

22B‧‧‧electrode

23‧‧‧Discharge gap filling member

24‧‧‧discharge gap

31‧‧‧Electrostatic discharge protection

32A‧‧‧electrode

32B‧‧‧electrode

33‧‧‧Discharge gap filling member

34‧‧‧discharge gap

35‧‧‧Protective layer

41‧‧‧Electrostatic discharge protection

42A‧‧‧Electrical conductor (exposed part is electrode)

42B‧‧‧Electrical conductor (exposed part is electrode)

43‧‧‧Insulation substrate

44‧‧‧Discharge gap filling member

45A‧‧‧ hole for insulating substrate

45B‧‧‧ hole for insulating substrate

46‧‧‧Width of discharge gap

[Fig. 1] Fig. 1 is a longitudinal sectional view showing an electrostatic discharge protector 11 as a specific example of the electrostatic discharge protector of the present invention.

[Fig. 2] Fig. 2 is a longitudinal sectional view showing an electrostatic discharge protector 21 as a specific example of the electrostatic discharge protector of the present invention.

[Fig. 3] Fig. 3 is a longitudinal sectional view showing an electrostatic discharge protector 31 as a specific example of the electrostatic discharge protector of the present invention.

[Fig. 4] Fig. 4 is a view of the electrostatic discharge protector 41 as a specific example of the electrostatic discharge protector of the present invention viewed from above.

[Fig. 5] Fig. 5 is a longitudinal sectional view showing an electrostatic discharge protector 41 as a specific example of the electrostatic discharge protector of the present invention.

[Fig. 6] Fig. 6 is a scanning electron microscope (SEM) image of the surface-coated alumina particles prepared in Preparation Example 1. The long axis direction is measured with a dotted arrow, and the thickness direction is measured with a solid arrow.

Hereinafter, the present invention will be described in detail.

<Discharge gap filling composition>

The discharge gap filling composition of the present invention is characterized by comprising a metal powder (A1), an aluminum powder (A2), and a binder component (B), and at least the surface of the primary particles of the metal powder (A1)-based metal When a part of the aluminum powder (A2)-based primary particles of aluminum is not covered by a film composed of a hydrolyzed product of a metal alkoxide, the surface of the primary powder of the aluminum powder (A2) is not covered by a film composed of a hydrolyzed product of a metal alkoxide. .

In the present invention, the discharge gap refers to a space formed between a pair of electrodes, and the discharge gap filling composition is used to fill before The composition of the discharge gap. The primary particle refers to a state in which particles are not aggregated with other particles, and the primary particles are used in comparison with secondary particles capable of agglomeration.

[Metal Powder (A1)]

At least a part of the surface of the primary particles of the metal powder (A1)-based metal used in the present invention is coated with a film composed of a hydrolyzed product of a metal alkoxide.

In the metal powder (A1), at least a part of the surface of the primary particles of the metal is covered with a film composed of a hydrolyzed product of a metal alkoxide, and thus has a localized moderate insulating property and a high withstand voltage. The discharge gap filling composition containing the metal powder (A1) is electrically insulating at the time of normal operation, but is electrically conductive at a high voltage load during electrostatic discharge, and is restored by high voltage release. Insulation. As a result, it is considered that the electrostatic discharge protection system using the discharge gap filling composition exhibits an effective electrostatic discharge protection characteristic and is less susceptible to damage at a high voltage.

The metal atom system constituting the metal alkoxide is not particularly limited as long as it can react with water alone or with water and a hydrolysis catalyst to form a hydrolysis product. Further, in the present application, the metal atom is also made to contain a semimetal such as ruthenium, osmium or tin. The metal atom system is preferably magnesium, aluminum, gallium, indium, lanthanum, cerium, lanthanum, tin, titanium, zirconium, hafnium, ytterbium or ytterbium. Among them, bismuth, titanium, zirconium, hafnium or tantalum is preferred, and bismuth is better.

The alkoxide of bismuth is not easy to enter due to moisture in the air. Since the hydrolysis is carried out and the hydrolysis rate is easily controlled, when the surface of the primary particles of the metal in the metal powder (A1) is coated with a film composed of a hydrolyzed product of alkoxide of cerium, the stability of the production becomes stable. It is better because it has a higher tendency.

The metal alkoxide is preferably represented by the following general formula (1). In the case of such a metal alkoxide, formation of a film of the hydrolyzate tends to be easy.

In the above general formula (1), M is a metal atom, O is an oxygen atom, R is each independently an alkyl group having 1 to 20 carbon atoms, and n is an integer of 1 to 40.

The M system in the above general formula (1) is preferably ruthenium, titanium, zirconium, hafnium or tantalum. When M is such a metal atom, the voltage resistance of the electrostatic discharge protector finally obtained tends to be good.

In the above general formula (1), R is an alkyl group having 1 to 20 carbon atoms, and preferably an alkyl group having 1 to 12 carbon atoms. Examples of such an alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, and 1-methylbutyl group. 2-methylbutyl, 3-methyl Butyl, neopentyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1,2-dimethylpropyl, 1 -methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3 - dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, n - heptyl, n-octyl, n-fluorenyl, n-fluorenyl and n-dodecyl. Among them, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isopropyl and n-pentyl are preferred, with ethyl, n-propyl, n- Butyl is preferred.

When the number of carbon atoms of the alkyl group is large, the hydrolysis of the metal alkoxide represented by the above general formula (1) is stabilized. On the other hand, if the carbon number of the alkyl group is too large, the general formula is (1) The metal alkoxide shown is in a waxy state, and it tends to be difficult to uniformly disperse.

Further, in the metal alkoxide represented by the above general formula (1), if the number of n is too large, the viscosity of the metal alkoxide itself increases, and it becomes difficult to disperse, so n is an integer of 1 to 4. More ideal. In particular, the monomer (n=1 in the general formula (1)) has a situation in which a rapid reaction is caused, and a large amount of floating particles are generated, so that a dimer (n=2 in the general formula (1)), three is used. A condensate of a polymer (n=3 in the general formula (1)) and a tetramer (n=4 in the general formula (1)) is preferred.

The metal alkoxide used in the present invention may, for example, be tetramethoxy decane, tetraethoxy decane, tetraethyl titanate or tetraisopropyl. Titanate, tetra-n-butyl titanate, tetra-sec-butyl titanate, tetra-tert-butyl titanate, tetra-2 ethylhexyl titanate, tetraethyl zirconate , tetraisopropyl zirconate, tetra-n-butyl zirconate, tetra-sec-butyl zirconate, tetra-tert-butyl zirconate, tetra-2 ethylhexyl zirconate, etc. The condensate is preferably tetraethoxy decane from the viewpoint of hydrolyzability and dispersibility. These metal alkoxides may be used singly or in combination of two or more.

A method of coating the surface of the primary particles of the metal in the metal powder (A1) with a film composed of the hydrolysis product of the metal alkoxide, for example, by using the metal powder (A1) in a solvent A method in which a metal alkoxide and a water which can be hydrolyzed by the amount thereof are gradually added in a suspended state. According to this method, a hydrolyzate containing a metal oxide or the like can be formed from the metal alkoxide, and the surface of the primary particles of the metal in the metal powder (A1) can be coated with the hydrolyzate.

In the metal alkoxide represented by the above general formula (1), for example, when M is ruthenium, an oligo which is formed by hydrolysis to form cerium oxide or a decyl alcohol group in a form of dehydration condensation or polymerization is used. A mixture of the material and the like, a film made of a metal oxide such as cerium oxide, coats the surface of the primary particles of the metal in the metal powder (A1).

The method of adding the metal alkoxide and water may be one-time addition, or may be added in a small amount in a plurality of stages. The order of addition may be that the metal alkoxide is dissolved or suspended in a solvent before adding water, or the metal alkoxide is added after dissolving or suspending the water in the solvent, or may be interlaced at a time. add plus. However, in general, since the reaction is stable, there is a tendency for the generation of floating particles to be small. Therefore, it is preferable to carry out the addition in a small amount in a plurality of stages, and to reduce the concentration in the solvent as needed. The state is added as better.

The solvent is preferably a metal alkoxide which dissolves alcohol, mineral spirits, solvent naphtha, benzene, toluene, xylene, petroleum ether, ether, etc., but is not particularly limited because it is reacted in suspension. Further, these may be used alone or in combination of two or more. Further, in the hydrolysis reaction of the metal alkoxide, alcohol is added as a by-product of the addition of water, so that alcohol can be used as a regulator of the polymerization rate.

The metal of the metal powder (A1) used in the present invention may be a generally known metal powder, but the metal of the metal powder (A1) is preferably a so-called passive state, and the metal tends to ionize. Large, but still able to complete the dense self-oxidation film on the surface of the metal of the primary particles, while protecting the interior. Examples of the metal element of such a metal include manganese, cerium, zirconium, hafnium, tantalum, molybdenum, vanadium, nickel, cobalt, chromium, magnesium, titanium, and aluminum, but aluminum is used in view of the fact that it is easy to obtain at a low price. Nickel, niobium and titanium are preferred, and aluminum is preferred.

These metal systems may be used alone or in combination of two or more.

The surface of the primary particles of the metal coated with the hydrolyzate of the metal alkoxide may also have a metal oxide film in advance. At this time, the self-oxidation film is present inside the coating of the hydrolyzed product of the metal alkoxide of the primary particles of the metal.

The method of forming the self-oxidation film on the surface of the primary particles of the metal may, for example, be a method of heating the metal in the presence of oxygen to form the self-oxidation film, but a more stable structure can be formed by the following method. Self-oxidizing film. That is, if the surface of the primary particles of the metal is cleaned with an organic solvent such as acetone, the surface of the primary particles of the metal is slightly etched with dilute hydrochloric acid, and 20% of hydrogen and 80% of argon are used. In the mixed gas atmosphere, the temperature is lower than the melting point of the metal itself, for example, 750 ° C in the case of a metal other than aluminum, and in the case of aluminum, for example, 600 ° C, heating for about 1 hour, further When heated in a high-purity oxygen atmosphere for 30 minutes, a uniform self-oxidizing film having high controllability and good reproducibility can be formed on the surface of the primary particles of the metal.

In the method of coating the surface of the primary particles of the metal in the metal powder (A1) with a film composed of a hydrolyzed product of a metal alkoxide as described above, the film thickness of the coating film can be made 10 nm to 2 μm. about. The film thickness of the coating film can be obtained by, for example, a transmission electron microscope. The coated region may be such that a part of the surface of the primary particle of the metal in the metal powder (A1) is covered by a film composed of a hydrolyzed product of a metal alkoxide, but the entire surface of the primary particle of the metal is It is preferred that the film composed of the hydrolyzate of the metal alkoxide is coated.

Further, the shape of the primary particles of the metal in the metal powder (A1) used in the present invention is preferably in the form of a sheet.

In the present invention, the sheet-like shape means a shape having a small thickness and a wide surface, and includes, for example, a shape such as a scaly shape, a disk shape, a long shape, or a layer shape, and does not include a spherical shape or the like. Specifically, for metal powder The thickness and surface of the primary particles of the metal in the last (A1) are in the form of flakes when the maximum length of the surface is twice or more the average thickness.

The length (d) of the shortest axis (short side) of the primary particles of the metal in the metal powder (A1) is preferably 1 μm or less and 0.05 μm or more, preferably 0.5 μm or less, and most preferably 0.3 μm. the following.

In the discharge gap filling composition of the present invention, the shape of the primary particles of the metal in the metal powder (A1) is in the form of a sheet, and the discharge of the electrostatic discharge protector using the discharge gap filling composition is used. The motility becomes a good tendency.

The preferred shape of the primary particles of the metal in the metal powder (A1) is such that the thickness of the particles, that is, the length of the shortest axis (short side) of the primary particles of the metal, is "d", and The maximum length of the face, that is, the average aspect ratio (L/d) when the length of the longest axis (long side) of the primary particles of the metal is "L" is expressed.

Further, the primary particles of the metal in the metal powder (A1) have an average aspect ratio (L/d) of preferably 3 or more and 1,000 or less, more preferably 5 or more and 500 or less, and more preferably 9 or more and 100 or more. The following is even better. The flaky particles are within the range of the aspect ratio described above.

In the discharge gap filling composition of the present invention, when the primary particles of the metal in the metal powder (A1) have an average aspect ratio (L/d) within the above range, it is easier to discharge the discharge direction smoothly. As a result, the electrostatic discharge protector using the discharge gap filling composition is excellent in the operating voltage and the withstand voltage. That is to say It is considered that the operability as a protective body is good, and for a discharge of a lower voltage, a characteristic that can serve as a protective body is also exhibited.

Further, the aspect ratio (L/d) of the primary particles of the metal in the metal powder (A1) was measured in the following manner. The metal powder (A1) formed by the cross section was observed under a scanning electron microscope at 1000 to 2000 times. Ten primary particles are arbitrarily selected from among the primary particles of the metal in the observed metal powder (A1), and the length "L" of the longest axis (long side) is measured among the selected primary particles, and This corresponds to the length "d" of the shortest axis (short side). The average aspect ratio (L/d) can be obtained by the average of L and d thus obtained.

The average particle diameter of the primary particles of the metal in the metal powder (A1) is preferably 1 μm or more and 15 μm or less, more preferably 3 μm or more and 11 μm or less. When the average particle diameter of the primary particles of the metal in the metal powder (A1) exceeds the above range, the surface energy becomes small, and therefore the force of the hydrolyzed product of the metal alkoxide adhered to the surface of the metal powder becomes small. As a result, in the discharge gap-filling composition, there are many cases in which the hydrolyzate of the metal alkoxide which does not adhere to the metal powder floats, and the operability after the formation of the electrostatic discharge protector is lowered. If the average particle diameter of the primary particles of the metal in the metal particles (A1) does not reach the above range, it is observed that the particles are strongly agglomerated with each other, so that a poor dispersion and uneven coating phenomenon are formed when reacting with the metal alkoxide. Further, since the ratio of the conductive portion of the core to the insulating layer of the coating layer becomes extremely small, the electric resistance at the time of electrostatic discharge is not easily lowered.

In addition, the average particle size in this specification is as long as there is no special record. The load is a value estimated by accumulating 50% by mass. The 50% by mass cumulative sample is weighed in 50 mg of the sample, added to 50 mL of distilled water, and further added with 2% Triton (GE Healthcare Bio-Sciences, Inc.) The surfactant of the surfactant is 0.2 ml of an aqueous solution, and after dispersing for 3 minutes with a 150 W ultrasonic homogenizer, a laser diffraction type particle size distribution meter such as a laser diffraction type light scattering particle size distribution meter (trademark: MICROTRACK MT3300, manufactured by Nikkiso Co., Ltd.) was measured.

[aluminum powder (A2)]

The surface of the primary particles of the aluminum powder (A2)-based aluminum is not covered by the hydrolyzate of the metal alkoxide. The surface of the primary particle is not covered by the hydrolyzate of the metal alkoxide, and the entire surface of the primary particle is not covered by the hydrolyzate of the metal alkoxide, and for example, aluminum itself is used on the surface of the primary particle of aluminum. Forming an oxide film or the like. The method of forming the self-oxidation film on the surface of the primary particles of aluminum includes the same method as that described for the metal powder (A1), but it is also possible to place the aluminum powder in the air.

The aluminum powder (A2) serves as a conductive ground portion, and substantially forms a parallel circuit or a series circuit in the discharge gap filling member formed by the discharge gap filling composition in a wide discharge gap.

Further, the primary particles in the aluminum powder (A2) have an average aspect ratio (L/d) of preferably 3 or more and 1,000 or less, more preferably 5 or more and 500 or less, and more preferably 10 or more and 100 or less. Better. needle The definition and measurement method of the aspect ratio are the same as those stated in the item of metal powder (A1).

The shape of the primary particles in the aluminum powder (A2) used in the present invention is preferably in the form of flakes. In the discharge gap filling composition of the present invention, the shape of the primary particles in the aluminum powder (A2) is in the form of a sheet, and the discharge of the electrostatic discharge protector using the discharge gap filling composition is activated. Sex becomes a good tendency. The definition of the flake shape and the average aspect ratio are the same as those stated in the item of the metal powder (A1).

The primary particle in the aluminum powder (A2) may have a length (d) of the shortest axis (short side) of 5 μm or less, preferably 3 μm or less, and most preferably 1 μm or less.

In the discharge gap filling composition of the present invention, when the primary particles in the aluminum powder (A2) have an average aspect ratio (L/d) within the above range, it is easier to discharge the discharge direction smoothly. As a result, the electrostatic discharge protector using the discharge gap filling composition is excellent in the operating voltage and the withstand voltage. In other words, it is considered that the operability as a protective body is good, and for a discharge of a lower voltage, a characteristic that can serve as a protective body is also exhibited.

The average particle diameter of the primary particles in the aluminum powder (A2) is preferably 5 μm or more and 70 μm or less, and more preferably 15 μm or more and 50 μm or less. When the average particle diameter is less than the above range, the number of aluminum powders (A2) having a small number of micrometers without an insulating film is increased, and when the electrostatic discharge is applied, the particles of the aluminum powder (A2) are easily moved to connect the particles to each other. Become Easy to short circuit. Further, when the average particle diameter exceeds the above range, even if it is between a wide electrode of, for example, about 300 μm to 1 mm, a small amount of aluminum powder (A2) particles are connected, and the tendency of electric resistance during general operation is not retained. .

The shape of the primary particles of the aluminum powder (A2) is represented by a water surface diffusion area WCA (m ² /g) in addition to the average aspect ratio and the average particle diameter. In general, the WCA of the flaky aluminum powder is in the range of 0.1 to 2 m ² /g, but the WCA of the preferred flaky aluminum powder of the present invention is 0.5 m ² /g or more, preferably 0.9 m ² /g or more.

Further, in the evaluation of WCA, flaky aluminum powder was powdered using acetone, and it was determined according to JIS K5906-1998.

[Combination of metal powder (A1) and aluminum powder (A2)]

The insulating property of the metal powder (A1) is greater than that of the aluminum powder (A2). As described above, the discharge gap-filling composition of the present invention which uses two kinds of metal powders having different insulating properties is excellent in the operability at the time of discharge even when it is used for filling between a wide discharge gap of, for example, 300 μm or more. It exhibits insulation in terms of voltage during normal operation.

In the case where the discharge gap filling composition of the present invention does not contain the aluminum powder (A2), it is difficult to obtain a performance unevenness after forming an electrostatic discharge protector having a wide discharge gap of, for example, 300 μm or more. Activism. In addition, in the case where the discharge gap filling composition does not contain the metal powder (A1), the insulation property in the case of the general operation is not maintained, or the insulation property is hard to be restored when the high voltage is released. Disadvantages. When the width of the discharge gap is wider than, for example, 300 μm, the mobility can be controlled by blending the metal powder (A1) with the aluminum powder (A2).

In the mass ratio of the metal powder (A1) to the aluminum powder (A2) in the discharge gap filling composition of the present invention, the metal powder (A1): aluminum powder (A2) is preferably 98:2 to 20:80, more preferably 95:5~35:65. When the mass ratio of the metal powder (A1) exceeds the above ratio, the voltage at the time of discharge operation becomes the same as that in the case where no aluminum powder (A2) is added. Further, when the mass ratio of the metal powder (A1) is less than the above ratio, there is a case where the insulation at the time of normal operation is insufficient, or the probability of short-circuiting due to application of a high voltage is increased.

The metal powder (A1) is coated with a hydrolyzed product of a metal alkoxide, and since the surface exhibits high insulating properties, even if the metal powder (A1) and the aluminum powder (A2) or (A1) are in contact with each other, There is no problem with the insulation during normal operation. Further, in the case where the width of the discharge gap is wider than a width of, for example, 300 μm, even if the aluminum powders (A2) having low insulating properties are in contact with each other, it is impossible to completely connect the discharge gaps. Therefore, from the viewpoint of the operability, the content of the metal powder (A1) and the aluminum powder (A2) in the discharge gap filling composition is considered to have no upper limit. However, when the content of the binder component (B) in the composition is small, problems such as falling powder may occur. Therefore, when the practicality is not considered as compared with the viewpoint of the activism, the total content of the metal powder (A1) and the aluminum powder (A2) is preferably 95% by mass or less based on the solid content of the discharge gap filling composition. .

In addition, since the electrostatic discharge protector must exhibit overall conductivity when ESD occurs, the total content of the metal powder (A1) and the aluminum powder (A2) is determined by the solid content of the discharge gap filling composition. More than 3 mass% is preferred.

Therefore, when the discharge gap filling composition of the present invention is used for an electrostatic discharge protector, the total content of the metal powder (A1) and the aluminum powder (A2) in the solid content of the discharge gap filling composition is discharged. The solid content of the gap-filling composition is preferably 3% by mass or more and 95% by mass or less, more preferably 30% by mass or more and 80% by mass or less.

Further, from the foregoing point of view, the discharge gap of the present invention The mass ratio (A/B) of the total mass of the metal powder (A1) and the aluminum powder (A2) in the solid content of the filling composition to the binder component (B) to be described later is 3/97 to 95/ 5 is better, with 30/70~80/20 being better.

[Binder composition (B)]

In the present invention, the binder component (B) means an insulator material for dispersing the above metal powder (A1) and aluminum powder (A2). Examples of the binder component (B) include an organic polymer, an inorganic polymer, or a composite polymer thereof.

Specific examples of the binder component (B) include a polyoxyalkylene compound, a urethane resin, a polyamidene, a polyolefin, a polybutadiene, an epoxy resin, a phenol resin, an acrylic resin, and a hydrogenation polymerization. Butadiene, poly Ester, polycarbonate, polyether, polyfluorene, polytetrafluoro resin, melamine resin, polyamide, polyamidimide, phenolic resin, unsaturated polyester resin, vinyl ester resin, alkyd resin, ethylene A base resin, an alkyd resin, a diallyl phthalate resin, an allyl ester resin, a furan resin, a rosin, a rosin derivative, a rubber derivative or the like.

Further, the binder component (B) is preferably a thermosetting compound or an active energy ray-curable compound from the viewpoint of mechanical stability, thermal stability, chemical stability, or stability over time. Among the thermosetting compounds, a thermosetting uric acid is used because the insulating resistance is high, the adhesion to the substrate is good, and the dispersibility of the metal powder (A1) and the aluminum powder (A2) is good. Ester resins are particularly desirable.

The compound contained in the binder component (B) may be used alone or in combination of two or more.

The thermosetting urethane resin may, for example, be a polymer having a urethane bond formed by reacting a polyol compound containing a carbonate diol compound with an isocyanate compound. Among them, a combination of a carbamate compound containing a carboxyl group-containing polyurethane resin, an epoxy group, an acid anhydride group, a carboxyl group, an alcohol group or an amine group, and an epoxy compound; and a carboxyl group and an alcohol group are preferable. Or a combination of an amine-based carbamate compound and a carbodiimide-containing compound. Examples of the epoxy compound include bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, and phenol. Novolak type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, N-glycidyl epoxy resin, phenolic varnish type ring of bisphenol A Oxygen resin, chelating epoxy resin, glyoxal type epoxy resin, amine-containing epoxy resin, rubber modified epoxy resin, caprolactone modified epoxy resin, etc., having two or more in one molecule An epoxy group compound. Further, in order to impart flame retardancy, an epoxy compound in which a halogen such as chlorine or bromine or an atom such as phosphorus is introduced into the structure may be used.

Further, from the viewpoint of having a hardening reaction function with other hardening components, a carboxyl group-containing thermosetting urethane resin having a carboxyl group in a molecule or an acid anhydride group having an acid anhydride group at a molecular terminal is further used. A thermosetting urethane resin is preferred.

Further, the other hardening component may be an epoxy resin curing agent or the like, and may be used as one of the binder components (B).

The carbonate diol compound may be a carbonate diol compound containing one or more kinds of repeating units derived from a linear aliphatic diol as a structural unit, and one or more kinds derived from an alicyclic formula. The repeating unit of the alcohol is a carbonate diol compound of a structural unit or a carbonate diol compound containing a repeating unit of the diol derived from the two as a structural unit.

A carbonate diol compound containing a repeating unit derived from a linear aliphatic diol as a structural unit, which is exemplified by having a carbonate bond-bonded 1,3-propanediol, 1,4-butanediol, 1,5 - diols such as pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol A polycarbonate diol having the structure of the composition.

A carbonate diol compound containing a repeating unit derived from an alicyclic diol as a structural unit, which may be exemplified by having a carbonate bond 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,3-cyclohexanediol, tricyclohexanedimethanol, pentacyclic ten A polycarbonate diol having a structure of a diol component such as pentacyclodiol. These diol components may be combined in two or more types.

The carbonate diol compound is commercially available from Daicel Chemical Co., Ltd. under the trade names PLACCEL, CD-205, 205PL, 205HL, 210, 210PL, 210HL, 220, 220PL, 220HL, and Ube Industries. The trade names of UC-CARB100, UM-CARB90, UH-CARB100, and Kuraray Co., Ltd. are trade names C-1065N, C-2015N, C-1015N, C-2065N, etc.

These carbonate diol compounds can be used singly or in combination of two or more. Among these, in particular, a carbonate diol compound containing a repeating unit derived from a linear aliphatic diol as a structural unit tends to be excellent in low warpage and flexibility. Therefore, when the binder component (B) containing the polycarbonate diol is used, it is easy to provide an electrostatic discharge protector to be described later on the flexible wiring board.

In addition, the carbonate diol compound containing a repeating unit derived from an alicyclic diol as a structural unit tends to have improved crystallinity and excellent heat resistance. In view of the above, these polycarbonate diols are used in combination of two or more kinds, or a polycarbonate containing a repeating unit derived from both a linear aliphatic diol and an alicyclic diol as a structural unit. A diol is preferred. In order to balance the flexibility and heat resistance, the ratio of the copolymerization ratio of the linear aliphatic diol to the alicyclic diol is 3:7 to 7:3. Suitable for.

Further, the number average molecular weight of the carbonate diol compound is preferably 5,000 or less. When the number average molecular weight exceeds 5,000, the amount of the relative urethane bond decreases, and thus the operating voltage of the electrostatic discharge protector rises or the withstand voltage decreases.

Specific examples of the above isocyanate compound include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and diphenylmethylene diisocyanate. , m, or p)-xylene diisocyanate, (o, m, or p)-hydroxylene diisocyanate, methylene bis(cyclohexyl isocyanate), trimethylhexamethylene diisocyanate, cyclohexane -1,3-dimethylene diisocyanate, cyclohexane-1,4-dimethylene diisocyanate, 1,3-trimethylene diisocyanate, 1,4-tetramethylene diisocyanate, 2, 2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,9-nonamethylene diisocyanate, 1,10-decamethylene Isocyanate, 1,4-cyclohexane diisocyanate, 2,2'-diethyl ether diisocyanate, cyclohexane-1,4-dimethylene diisocyanate, 1,5-naphthalene diisocyanate, p-stretch Phenyl diisocyanate, 3,3'-methylenedimethylphenylene-4,4'-diisocyanate, 4,4'-diphenyl ether diisocyanate, tetrachlorophenylene diisocyanate, norbornane Diisocyanate And 1,5-naphthalene diisocyanate, etc. diisocyanate. These isocyanate compounds may be used alone or in combination of two or more.

Among these, an alicyclic diisocyanate derived from an alicyclic diamine, specifically, isophorone diisocyanate or (o, m, or p)-hydroxylene diisocyanate is preferred. When such a diisocyanate is used, a cured product excellent in withstand voltage can be obtained.

In the thermosetting urethane resin used in the present invention, in particular, in order to obtain the carboxyl group-containing thermosetting urethane resin, a polyol having a carboxyl group and, for example, the above-described carbonate diol compound and the aforementioned isocyanate compound may be used. Just react together.

The polyol having a carboxyl group is particularly preferably a dihydroxy aliphatic carboxylic acid having a carboxyl group. Examples of such a dihydroxy compound include dimethylolpropionic acid and dimethylolbutanoic acid. The carboxyl group can be easily present in the urethane resin by using a dihydroxy aliphatic carboxylic acid having a carboxyl group.

The thermosetting urethane resin used in the present invention, in particular, in order to obtain the above-mentioned acid anhydride group-containing thermosetting urethane resin, for example, a second diisocyanate compound and a polycarboxylic acid having an acid anhydride group or The second diisocyanate compound is obtained by reacting the above-described carbonate diol compound with the above isocyanate compound so that the ratio of the number of hydroxyl groups to the number of isocyanate groups is such that the ratio of the number of hydroxyl groups to the number of isocyanate groups is 1.0 or more.

The polyvalent carboxylic acid having an acid anhydride group and a derivative thereof may, for example, be a trivalent polycarboxylic acid having an acid anhydride group and a derivative thereof, and a tetravalent polycarboxylic acid having an acid anhydride group.

The trivalent polycarboxylic acid having an acid anhydride group and a derivative thereof are not particularly limited, and examples thereof include a compound represented by the following formula (2) and the following formula (3).

(wherein R' represents hydrogen, an alkyl group having 1 to 10 carbon atoms or a phenyl group, and Y ¹ is -CH ₂ -, -CO-, -SO ₂ -, or O-).

The trivalent carboxylic acid having an acid anhydride group and a derivative thereof are particularly preferred from the viewpoint of heat resistance and cost, and trimellitic anhydride.

Further, a tetracarboxylic dianhydride, an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid other than the above polyvalent carboxylic acid and its derivative may be used as needed.

Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3', 4,4'-diphenyl ketone tetracarboxylic dianhydride, and 3,3',4,4'-biphenyl tetra Carboxylic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic acid Acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 3,4,9,10-decanetetracarboxylic dianhydride, 4,4'-sulfonyldiphthalic dianhydride, M-tert-phenyl-3,3',4,4'-tetracarboxylic dianhydride, 4,4'-oxydiphthalic acid Dihydride, 1,1,1,3,3,3-hexafluoro-2,2-bis(2,3- or 3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis (2, 3- or 3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis[4-(2,3- or 3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 1,1 , 1,3,3,3-hexafluoro-2,2-bis[4-(2,3- or 3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 1,3-double (3 ,4-dicarboxyphenyl)-1,1,3,3-tetramethyldioxanane dianhydride, butane tetracarboxylic dianhydride, bicyclo-[2,2,2]-oct-7-ene -2:3:5:6-tetracarboxylic dianhydride or the like.

Examples of the aliphatic dicarboxylic acid include succinic acid, glutaric acid, adipic acid, sebacic acid, suberic acid, sebacylic acid, sebacic acid, dodecanedioic acid, and dimer acid. Wait.

Examples of the aromatic dicarboxylic acid include isophthalic acid, terephthalic acid, phthalic acid, naphthalene dicarboxylic acid, and oxydibenzoic acid.

Further, a monohydroxy compound which is an end-blocking agent when the thermosetting urethane resin is produced is preferably used. The monohydroxy compound is not particularly limited as long as it has a hydroxyl group in the molecule, and examples thereof include an aliphatic alcohol and a monohydroxy mono(meth)acrylate compound. Here, the (meth) acrylate means acrylate and/or methacrylate, and is the same as the following.

Examples of the aliphatic alcohols include methanol, ethanol, propanol, and isobutanol, and examples of the monohydroxy mono(meth)acrylate compound include 2-hydroxyethyl acrylate. By using this, it is possible to avoid the residual isocyanate group in the thermosetting urethane resin.

In the thermosetting urethane resin, it may further In order to impart flame retardancy, atoms such as halogen or phosphorus such as chlorine or bromine are introduced into the structure.

In the case where the blending ratio of the carbonate diol compound and the isocyanate compound is the same, the thermosetting urethane resin containing the acid anhydride group is excluded, preferably a molar ratio of 50:100 to 150. :100, more preferably 80:100~120:100.

In particular, when a carboxyl group-containing thermosetting urethane resin is obtained, a blend ratio when a polyol having a carboxyl group is reacted with the carbonate diol compound and the isocyanate compound is referred to as a carbonate diol compound ( a), isocyanate compound (b), polyol (c) having a carboxyl group, the molar ratio is (a) + (c): (b) = 50: 100 to 150: 100, more preferably (a) + (c): (b) = 80: 100 ~ 120: 100.

The solvent used in the reaction between the polyol compound containing the carbonate diol compound and the isocyanate compound is an ether solvent, a sulfur-containing solvent, an ester solvent, a ketone solvent, an aromatic hydrocarbon solvent, or the like. Non-nitrogen-based polar solvents are preferred.

For example, examples of the ether solvent include diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether.

Examples of the sulfur-containing solvent include dimethyl hydrazine, diethyl hydrazine, dimethyl hydrazine, and cyclobutyl hydrazine.

Examples of the ester solvent include γ-butyrolactone, diethylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether. Acetate, diethylene glycol monoethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monoethyl ether acetate.

Examples of the ketone solvent include cyclohexanone and methyl ethyl ketone.

Examples of the aromatic hydrocarbon solvent include toluene, xylene, and naphtha.

These solvents may be used alone or in combination of two or more.

Among these, a solvent which is highly volatile and can impart low-temperature hardenability is more preferably γ-butyrolactone, diethylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, Propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monoethyl ether acetate, and the like.

The reaction temperature of the polyol compound containing the above carbonate diol compound and the above isocyanate compound is preferably from 30 to 180 ° C, more preferably from 50 to 160 ° C. When the temperature is lower than 30 ° C, the reaction becomes too long, and if it exceeds 180 ° C, gelation tends to occur.

The reaction time varies depending on the reaction temperature, but is preferably from 2 to 36 hours, more preferably from 8 to 16 hours. In the case of less than 2 hours, it is difficult to control even if the reaction temperature is raised in order to obtain a desired number average molecular weight. In addition, in the case of more than 36 hours, it is not practical.

The above-mentioned thermosetting urethane resin preferably has a number average molecular weight of 500 to 100,000 and more preferably 8,000 to 50,000. Here, the number average molecular weight is a value in terms of polystyrene measured by gel permeation chromatography. Number average molecule of thermosetting urethane resin When the amount is less than 500, the elongation, flexibility, and strength of the cured film may be impaired, and if it exceeds 1000,000, it may become hard, which may reduce the flexibility.

In particular, the acid value of the carboxyl group-containing thermosetting urethane resin is preferably 5 to 150 mgKOH/g, more preferably 30 to 120 mgKOH/g. When the acid value is less than 5 mgKOH/g, the reactivity with the curable component is lowered, and the desired heat resistance or long-term reliability cannot be obtained. When the acid value exceeds 150 mgKOH/g, flexibility may easily disappear, and long-term insulation properties and the like may be lowered. Further, the acid value of the resin is a value measured in accordance with JIS K5407.

Examples of the active energy ray-curable compound include an acrylic copolymer containing a compound of two or more ethylenically unsaturated groups, an epoxy (meth) acrylate resin, and a urethane (meth) acrylate resin.

The content of the binder (B) is a value obtained by removing the content of the component (A1), the component (A2), and other components added as needed from the entire discharge gap filling composition, and the solid content of the discharge gap filling composition. In particular, it is preferably 5% by mass or more and 97% by mass or less, more preferably 20% by mass or more and 70% by mass or less.

[Other ingredients]

The discharge gap filling composition of the present invention contains the metal powder (A1), aluminum powder (A2), and binder component (B), and may contain a layered substance, a curing catalyst, a hardening accelerator, and a filler as needed. Agent, solvent, foaming agent, antifoaming agent, leveling agent, slip agent, plasticizer, rust inhibitor, Viscosity adjusters, colorants, etc. Further, insulating particles such as cerium oxide particles may be contained.

[Method of Manufacturing Composition for Discharge Gap Filling]

The discharge gap filling composition of the present invention can be, for example, a metal powder (A1) or an aluminum powder by using a diaper, a kneader, a three-roll mill, a bead mill, a self-rotating mixer, or the like. (A2) and the binder component (B) are produced by dispersing and mixing a solvent, a filler, a curing catalyst, or the like as another component. At the time of mixing, in order to make compatibility favorable, it can heat to a sufficient temperature. After the above dispersion and mixing, it may be prepared by further adding a hardening accelerator as needed to be mixed.

<electrostatic discharge protection body>

The electrostatic discharge protector of the present invention is an electrostatic discharge protector having at least two electrodes and a discharge gap between the two electrodes, and is characterized in that the discharge gap filling composition is filled in the discharge gap. The formed discharge gap filling member.

The two electrodes are arranged at a constant distance. The space between the two electrodes is a discharge gap. The discharge gap filling member is formed in the discharge gap. That is, the two electrodes are connected to each other through the discharge gap filling member. The discharge gap filling member is formed by the above-described discharge gap filling composition.

One of the states of the electrostatic discharge protector of the present invention A plate-shaped insulating base having two conductors disposed at a predetermined interval and having two holes and having one hole and the other hole facing each other on the respective conductors And an electrostatic discharge protector of the discharge gap filling member filled to cover at least a portion of the insulating substrate,

The insulating base material is disposed such that at least a portion of the electrode of each of the conductors is exposed and extends across the two conductors, and the two holes of the insulating base material are filled by the discharge gap filling member Covering, forming a discharge gap in the closest part of the two.

The electrode in the above-described state is a portion which is not covered by the insulating base material of the above two conductors. Further, the distance between the conductors in the place where the two holes are closest to each other, that is, the distance between the shortest distance between the two holes and the thickness of the insulating base material is twice the width of the discharge gap. The discharge gap filling member is formed in the discharge gap. That is, the two conductive systems are connected to each other through the discharge gap filling member. The discharge gap filling member is formed by the above-described discharge gap filling composition.

The electrostatic discharge protection system of the present invention is used as a protection circuit for flowing an overcurrent to the ground to protect the device during electrostatic discharge.

Since the electrostatic discharge protector of the present invention has a discharge gap filling member formed by filling the discharge gap filling composition in the discharge gap, it is excellent in insulation, operating voltage, and withstand voltage at the time of normal operation. That is, the electrostatic discharge protection system of the present invention can be used in general When the voltage is low at the time of actuation, a high electrical resistance value is exhibited, and the current is not supplied to the ground and supplied to the device. On the other hand, after the electrostatic discharge is generated, the low electrical resistance value can be immediately exhibited, so that the overcurrent flows to the ground, and the overcurrent is prevented from being supplied to the device. After the transient phenomenon of electrostatic discharge is eliminated, the high resistance value can be returned and the current is supplied to the device.

Further, in the electrostatic discharge protector of the present invention, the discharge gap between the two electrodes is filled with the discharge gap filling composition of the insulating binder component (B), so that leakage current does not occur during normal operation. For example, it is possible to set an electrical impedance value of 10 ¹⁰ Ω or more after applying a voltage of DC 10 V or less between two electrodes, thereby achieving electrostatic discharge protection.

The electrostatic discharge protector of the present invention can be produced by forming the discharge gap filling member in the following manner by using the above-described discharge gap filling composition.

That is, first, the discharge gap filling composition is prepared by the above method. The discharge gap filling composition is applied by a method such as potting or screen printing so as to cover between the two electrodes or the two holes which are the discharge gaps, and is heated or hardened as necessary. A discharge gap filling member is formed.

The width of the discharge gap is preferably 300 μm or more and 1 mm or less, more preferably 400 μm or more and 1 mm or less, and still more preferably 600 μm or more and 800 μm or less. When the width of the discharge gap exceeds 1 mm, the operability at the time of electrostatic discharge tends to decrease. In addition, when it is less than 300 μm, it may be difficult to restore the insulation after electrostatic discharge, and There is a tendency to have uneven performance. Here, the width of the discharge gap means the shortest distance between the electrodes, and the case where the discharge gap filling composition of the present application exists between the discharge gaps means the shortest distance through which the current flows. Further, in the case where a difference in conductivity exists between the discharge gaps and only a portion having a relatively good conductivity is turned on, the width of the discharge gap means the shortest distance of the path of the conduction.

The preferred electrode shape of the electrostatic discharge protector can be arbitrarily set in accordance with the state of the circuit board. However, in consideration of miniaturization, a cross-sectional shape of a rectangular film may be exemplified, for example, a thickness of 20 ~200μm shape.

A preferred electrode width of the electrostatic discharge protector is 300 μm or more. If it is in the above range, the damage at the time of electrostatic discharge can be dispersed.

It is preferable that the electrostatic discharge protection system of the present invention has a protective layer formed on the surface of the discharge gap filling member.

The above-described discharge gap filling composition may have insufficient adhesion to the substrate depending on the material of the substrate having the discharge gap, or the electrostatic discharge may be extremely high energy, or may have metal powder (A1) and The content of the aluminum powder (A2) is high.

In the above-described case, the electrostatic discharge protector of the present invention can provide a higher voltage by providing a protective layer such as a resin composition to be described later so as to cover the discharge gap filling member after forming the discharge gap filling member. Resist and maintain excellent resistance to repeated resistance.

Examples of the resin used as the protective layer include a natural resin, a modified resin, and an oligomer synthetic resin.

The natural resin is represented by rosin. Examples of the modified resin include rosin derivatives, rubber derivatives, and the like. Examples of the oligomer-based synthetic resin include an anthracene resin and the like, and examples thereof include an epoxy resin, an acrylic resin, a maleic acid derivative, a polyester resin, and a melamine resin in combination with a polyoxyalkylene compound of an electrostatic discharge protector. A urethane resin, a quinone imine resin, a phthalic acid resin, a quinone imine/melamine resin, or the like.

Further, a resin composition can be used as the protective layer.

In order to retain the coating film strength, the resin composition preferably contains a curable resin which can be cured by heat or ultraviolet rays.

Examples of the thermosetting resin include a combination of a compound containing a carboxyl group-containing urethane resin, an epoxy compound, or an acid anhydride group, a carboxyl group, an alcohol group, and an amine group, and an epoxy compound; and a carboxyl group or an alcohol group; A combination of an amine group compound and a carbodiimide containing compound.

Examples of the epoxy compound include bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, and phenol novolac. Varnish type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, N-glycidyl epoxy resin, bisphenol A novolak type epoxy resin, chelating epoxy resin, B Dialdehyde type epoxy resin, amine-containing epoxy resin, rubber modified epoxy resin, dicyclopentadiene novolac type epoxy resin, polyfluorene modified epoxy resin, ε-caprolactone modified epoxy resin An epoxy compound having two or more epoxy groups in one molecule.

Further, in order to impart flame retardancy, an epoxy compound in which a halogen such as chlorine or bromine or an atom such as phosphorus is introduced into the structure may be used. Enter Alternatively, a bisphenol S type epoxy resin, a diglycidyl malonate resin, a heterocyclic epoxy resin, a bixylenol type epoxy resin, a bisphenol type epoxy resin, and a tetraglycidyl acid can also be used. An xylenol ethane resin or the like.

Examples of the ultraviolet curable resin include an acrylic copolymer containing a compound of two or more ethylenically unsaturated groups, an epoxy (meth) acrylate resin, and a urethane (meth) acrylate resin.

The resin composition forming the protective layer may contain a hardening accelerator, a filler, a solvent, a foaming agent, an antifoaming agent, a leveling agent, a slip agent, a plasticizer, a rust preventive agent, a viscosity adjuster, and a coloring as needed. Agents, etc.

The thickness of the protective layer is not particularly limited, but is preferably 0.1 μm to 1 mm. Further, the protective layer is preferably a discharge gap filling member formed by completely covering the composition for filling the gap gap. If the protective layer is defective, the possibility of cracking at high energy at the time of electrostatic discharge increases.

Fig. 1 is a longitudinal sectional view showing an electrostatic discharge protector 11 as a specific example of the electrostatic discharge protector of the present invention. The electrostatic discharge protector 11 is formed of the electrode 12A, the electrode 12B, and the discharge gap filling member 13. The electrode 12A and the electrode 12B are arranged such that the axial directions are aligned and the respective distal end faces are opposed to each other. A discharge gap 14 is formed between the opposing end faces of the electrode 12A and the electrode 12B. The discharge gap filling member 13 is formed in the discharge gap 14, and further faces the front end surface of the electrode 12A facing the front end surface of the electrode 12B and the front end surface of the electrode 12B facing the electrode 12A. The front end face of the part is placed in contact with the front end. The width of the discharge gap 14, that is, the distance between the electrode 12A facing each other and the front end surface of the electrode 12B is preferably 300 μm or more and 1 mm or less.

Fig. 2 is a longitudinal sectional view showing an electrostatic discharge protector 21 as another specific example of the electrostatic discharge protector of the present invention. The electrostatic discharge protector 21 is formed of an electrode 22A, an electrode 22B, and a discharge gap filling member 23. The electrode 22A and the electrode 22B are disposed so as to overlap the respective distal end faces in the vertical direction in parallel with each other. A discharge gap 24 is formed in a portion where the electrode 22A and the electrode 22B overlap in the vertical direction. The discharge gap filling member 23 has a rectangular cross section and is formed in the discharge gap 24 . The width of the discharge gap 24, that is, the distance between the electrode 22A and the electrode 22B in the portion where the electrode 22A and the electrode 22B overlap in the vertical direction is preferably 300 μm or more and 1 mm or less.

Fig. 3 is a longitudinal sectional view showing an electrostatic discharge protector 31 as a specific example of the electrostatic discharge protector of the present invention. The electrostatic discharge protector 31 is formed, for example, on a substrate made of a polyimide film, and is formed of an electrode 32A, an electrode 32B, a discharge gap filling member 33, and a protective layer 35. The electrode 32A and the electrode 32B are arranged such that the axial directions are aligned and the respective distal end faces are opposed to each other. A discharge gap 34 is formed between the opposing end faces of the electrode 32A and the electrode 32B. The discharge gap filling member 33 is formed in the discharge gap 34, and further has a front end surface which is opposed to the front end surface of the electrode 32B from the upper side cover electrode 32A, and a front end surface of the electrode 32B and the electrode 32A. The way to the front end face of the part is made to contact the front end. The width of the discharge gap 34, that is, the distance between the electrode 32A facing each other and the front end surface of the electrode 32B is preferably 300 μm or more and 1 mm or less.

Fig. 4 is a view showing a specific example of the electrostatic discharge protector 41 of the present invention, and Fig. 5 is an electrostatic longitudinal sectional view showing a broken line portion of the electrostatic discharge protector 41 of the present invention shown in Fig. 4. The electrostatic discharge protector 41 is composed of, for example, conductors 42A and 42B such as copper, an insulating base material 43 such as a glass epoxy substrate, and a discharge gap filling member 44. The conductors 42A and 42B are arranged at a specific interval. The insulating base material 43 is provided with two holes at a predetermined interval, and spans the conductors 42A and 42B as shown in FIG. 5, and does not cover the entire surfaces of the conductors 42A and 42B, and The two holes 45A and 45B are placed on the conductors 42A and 42B, respectively. The discharge gap filling member 44 blocks the two holes 45A and 45B of the insulating base material 43 and is formed on the insulating base material 43 and is connected to the conductors 42A and 42B through the two holes. The portion overflowing from the insulating base material 43 of the conductors 42A and 42B becomes an electrode. The distance between the portions closest to each other in the two holes of the insulating base material 43 and the distance 46 between the thicknesses of the insulating base materials are the widths of the discharge gaps at this time, and the thickness is 300 μm or more and 1 mm or less. It is better.

As described above, the discharge gap filling member formed of the discharge gap and the discharge gap filling composition does not necessarily have to be present on the same substrate. For example, if the substrate for IC chip mounting is used, even if it is absolutely The edge substrate is formed into two holes at intervals of 300 μm to 1000 μm so that two copper foil sheets are subsequently joined in such a manner as to block the respective holes, and if the insulating substrate is filled and discharged as in the case of two holes, The gap filling composition also becomes an electrostatic discharge protector.

[use]

The electronic circuit board of the present invention has the above-described electrostatic discharge protector. Therefore, the electronic circuit board of the present invention tends to be less susceptible to damage due to static electricity even when subjected to electrostatic discharge.

Further, the flexible electronic circuit board of the present invention has the above-described electrostatic discharge protector. Therefore, the flexible electronic circuit board of the present invention tends to be less susceptible to damage due to static electricity even when subjected to electrostatic discharge. The IC wafer mounting substrate of the present invention has the above-described electrostatic discharge protector. Therefore, the IC wafer mounting substrate of the present invention tends to be less susceptible to damage due to static electricity even when subjected to electrostatic discharge, and thus can be applied to smart cards, BGAs, CSPs, and COBs.

The electronic device of the present invention includes the electronic circuit board, the flexible electronic circuit board, or the IC chip mounting board. Therefore, the electronic device of the present invention tends to be less susceptible to damage due to static electricity even when subjected to electrostatic discharge.

[Examples]

Next, the embodiment of the present invention is shown to further detail It is to be noted that the invention is not limited thereby.

The respective characteristics of the electrostatic discharge protector obtained in the present example were evaluated as described below.

<Evaluation method of insulation when the voltage is normally applied>

For the electrode portions at both ends of the electrostatic discharge protector, an electric resistance meter "MEGOHMMETER SM-8220" (manufactured by DKK-TOA CORPORATION) was used to measure the electric resistance when DC 10 V was applied as "resistance during normal operation". Based on the measured value, the insulation at the normal operating voltage of the electrostatic discharge protector was evaluated using the following criteria.

(benchmark)

A: indicates that the electrical impedance is 10 ¹⁰ Ω or more.

B: indicates that the electrical impedance value is less than 10 ¹⁰ Ω

<Evaluation method of actuation voltage>

Using the semiconductor electrostatic tester ESS-6008 (manufactured by NOISE LABORATORY Co., Ltd.), the obtained electrostatic discharge protector was first applied at 500 V, and the applied voltage was increased by 50 V every time, and the applied voltage after the discharge current was passed was measured. "Operation voltage". After the discharge current was measured by the first 500 V application, the actuation voltage was set to 500V.

<Evaluation method of withstand voltage>

The electrostatic discharge protector was attached to a semiconductor static tester ESS-6008 (manufactured by NOISE LABORATORY Co., Ltd.), and after applying an applied voltage of 8 kV, an insulation resistance meter MEGOHMMETER SM-8220 was used to measure the resistance value when DC 10 V was applied. The resistance value was evaluated as "withstand voltage" by the following criteria.

(benchmark)

A: 10 ¹⁰ Ω or more is displayed even after ¹⁰ or more applications

B: If it is applied 5~9 times, it shows that it is less than 10 ⁵ Ω.

B: If it is applied 2~4 times, it shows that it is less than 10 ⁸ Ω.

B: If applied once, the display is less than 10 ⁸ Ω

The measured values in this embodiment were measured by the following methods.

Each numerical value in the present specification is a value obtained by the following measurement method.

<Average particle size>

The accumulated 50% by mass diameter was used to evaluate 50 mg of the sample, and 50 mg of the sample was added to 50 mL of distilled water, and 2% of Triton (trade name of surfactant prepared by GE Healthcare Bio-Sciences Co., Ltd.) was further added. 0.2ml of aqueous solution, dispersed by a 150W ultrasonic homogenizer for 3 minutes, using a laser diffraction type particle size distribution meter, such as a laser diffraction type light scattering particle size distribution meter (trademark: MICROTRACK MT3300, Nikkiso Co., Ltd. Measured.

<number average molecular weight>

The measurement was carried out by gel permeation chromatography and expressed in terms of polystyrene.

<acid price>

The measurement was performed in accordance with JIS K5407.

<Average aspect ratio>

A sample of 1 g was weighed, and 3 g of propylene glycol monomethyl ether was added thereto, and the mixture was dispersed for 3 minutes in an ultrasonic homogenizer outputting 150 W, and then 10 g of an acrylic resin (trade name: ACRIC #2000 KANSAI PAINT CO., LTD.) was added for stirring. It was coated on a quinone film and hardened at 150 ° C for 5 minutes. The cross section of the cured product was observed by a scanning electron microscope (trademark: JSM-5500LV, manufactured by JEOL Ltd.) at 1000 to 2000 times, and the length (L) and the shortest length (L) of the longest axis (long side) of any of the selected 10 primary particles were measured. The length (d) of the axis (short side) is evaluated for the average aspect ratio (L/d).

<electrostatic discharge protector C>

The electrostatic discharge protectors C1 to C11 used in the examples were produced in the following manner.

A wiring board having a pair of electrode patterns (film thickness: 12 μm, electrode width: 2 mm) was formed on a polyimide film having a thickness of 25 μm, and was coated with a needle having a needle tip diameter of 2 mm and a flat needle. Each of the discharge gap filling compositions was filled in the discharge gap pattern across the electrode pattern, and held in a thermostat at 150 ° C for 60 minutes to form a discharge gap filling member to form an electrostatic discharge protector.

The electrostatic discharge protector used for the evaluation of the operating voltage was such that the width of the discharge gap of the electrode pattern was 300 μm, 500 μm, and 1 mm.

<electrostatic discharge protector D>

The electrostatic discharge protectors D1 to D11 used in the examples were produced in the following manner.

A polyimine film "UPILEX 75S Ube Industries, Ltd." having a thickness of about 15 mm and a thickness of 75 μm was provided with two holes of about 4 mm square at intervals of 0.5 mm. Two sheets of copper-clad laminates having a size of about 10 mm square were prepared so that one side of the hole was attached to one hole so that the copper-plated side faces the hole. Two copper-clad laminates are placed in such a way that they do not touch each other. Each of the discharge gap-filling compositions obtained in the examples was applied by using a needle having a needle tip diameter of 2 mm and a flat needle across the two holes of the polyimide film, and held in a thermostat at 150 ° C for 60 minutes. A discharge gap filling member is formed to form an electrostatic discharge protector having the structure shown in Fig. 4 or Fig. 5.

<Preparation Example 1 of Metal Powder (A1)>

The surface of the aluminum particles is coated with a film composed of a hydrolysis product of a metal alkoxide as described below. Metal alkoxide is tetraethoxy oxime alkyl.

76 g of flaky aluminum particles (trade name: 2173, solid content: 65%, average aspect ratio: 68, average particle diameter: 9 μm) manufactured by Showa Aluminum Powder Co., Ltd. were dispersed in 724 g of propylene glycol monomethyl ether. To the dispersion, 169 g of ion-exchanged water and 32 g of 25 mass% aqueous ammonia were added and stirred to obtain an aluminum powder slurry. The liquid temperature of this aluminum powder slurry was maintained at 30 °C.

Next, 13.2 g of tetraethoxyoxane was diluted with 13.2 g of propylene glycol monomethyl ether. The dilution was dropped to the aluminum powder slurry at a specific speed for 12 hours to carry out surface coating of the aluminum particles by the hydrolysis product of tetraethoxyoxane.

After the dropping, stirring was continued for 12 hours, and the temperature was maintained at 30 °C. Thereafter, the reaction liquid was filtered to obtain an aluminum cake, and the obtained aluminum cake was washed with propylene glycol monomethyl ether. The washed aluminum cake was again dispersed in 500 g of propylene glycol monomethyl ether acetate, and heated at 110 ° C for 90 minutes, and then allowed to cool to room temperature. Then, the reaction liquid was filtered to obtain an aluminum cake. Thereafter, the solvent was dispersed at 40 ° C to obtain a paste containing aluminum propylene glycol monomethyl ether acetate (hereinafter referred to as "aluminum-containing powder paste A1-1") having an aluminum solid content of 41% by mass.

For the calculation of the solid content, the residue after drying 1 g of the removed paste at 120 ° C for 1 hour was divided by the amount of the paste before drying as a solid component. In addition, the scattering operation of the solvent at 40 ° C was completed after confirming that the solid content was 41% by mass.

<Modulation Example 2 of Metal Powder (A1)>

76 g of flaky aluminum particles (trade name: 2173, solid content: 65%, average aspect ratio: 68, average particle diameter: 9 μm) manufactured by Showa Aluminum Powder Co., Ltd., and 16.5 g of tetraethoxy decane dispersed in 400 g Propylene glycol monomethyl ether was heated at 110 ° C for 2 hours. After the dispersion was allowed to cool to room temperature, 180 g of ion-exchanged water and 12 g of 25% by mass aqueous ammonia were added and stirred for 1 hour. Further, 360 g of ion-exchanged water and 20 g of aqueous ammonia were added and stirred for 1 hour, and then the reaction liquid was filtered to obtain an aluminum cake. Further, the obtained aluminum cake was washed three times with propylene glycol monomethyl ether. The washed aluminum cake was again dispersed in 500 g of triacetin, heated at 110 ° C for 90 minutes, and then allowed to cool to room temperature. Thereafter, the reaction liquid was filtered to obtain an aluminum cake, and the obtained aluminum cake was washed three times with propylene glycol monomethyl ether acetate. After that, the solvent was dispersed at 40 ° C to obtain a paste containing aluminum propylene glycol monomethyl ether and water (hereinafter referred to as "aluminum-containing powder paste A1-2") having an aluminum solid content of 41% by mass.

<Synthesis Example of Binder Component (B)>

The binder component (B) before the addition of the curing agent is a thermosetting urethane resin synthesized in the following manner.

In a reaction vessel equipped with a stirring device, a thermometer, and a condenser, 718.2 g of C-1015N (polycarbonate diol manufactured by KURARAY CO., LTD, raw material diol molar ratio: 1,9-nonanediol) was charged. : 2-methyl-1,8-octanediol = 15:85, molecular weight 964) as polycarbonate II Alcohol, 136.6 g of 2,2-dimethylol phthalic acid (manufactured by Nippon Kasei Co., Ltd.) as a dihydroxy compound having a carboxyl group, and 1293 g of diethylene glycol ethyl ether acetate (DAICEL Chemical Co., Ltd.) As a solvent, all the raw materials were dissolved at 90 °C.

The temperature of the liquid in which the raw material was dissolved was lowered to 70 ° C, and 237.5 g of methylene bis(4-cyclohexyl isocyanate) (trade name, manufactured by Sumika Bayer Urethane Co., Ltd.) was dropped over 30 minutes by dropping the funnel. "Desmodur-W") as a polyisocyanate.

After the completion of the dropwise addition, the reaction was carried out at 80 ° C for 1 hour, at 90 ° C for 1 hour, and at 100 ° C for 1.5 hours. After the isocyanate was almost eliminated, 2.13 g of isobutanol was dropped (manufactured by Wako Pure Chemical Industries, Ltd.). Further, the reaction was further carried out at 105 ° C for 1 hour to obtain a carboxyl group-containing urethane resin (hereinafter also referred to as "thermosetting urethane resin").

The thermosetting urethane resin obtained had a number average molecular weight of 6090 and a solid content acid value of 40.0 mgKOH/g. To the obtained thermosetting urethane resin, γ-butyrolactone was added and diluted to obtain a solid content of 45% by mass to obtain a solution (hereinafter also referred to as "thermosetting urethane resin solution").

[Example 1] <Modulation of composition for discharge gap filling>

48.8 g of the aluminum-containing powder paste A1-1 (solid content: 41% by mass) and 13.2 g of Showa Aluminum Powder Co., Ltd. were prepared. The thermosetting urethane prepared by the synthesis example of the flaky aluminum powder A2-1 (trade name: 576PS, average particle diameter: 20 μm, solid content: 65 mass%, average aspect ratio: 23) and 37.8 g A resin solution (solid content: 45 mass%) and 1.9 g of an epoxy resin (trade name: JER604) manufactured by Japan epoxy rasin Co., Ltd. as a curing agent were stirred at 2000 rpm for 15 minutes using an ultrasonic homogenizer to obtain a discharge gap filling composition. Matter 1.

<Manufacture and evaluation of electrostatic discharge protectors>

The discharge gap-filling composition 1 was used, and the electrostatic discharge protector C1 and the electrostatic discharge protector D1 were obtained by the above-described method, and the insulation, the operating voltage, and the withstand voltage at the time of normal operation were evaluated. The results are shown in Table 1.

[Embodiment 2] <Modulation of composition for discharge gap filling>

48.8 g of the aluminum-containing powder paste A1-1 (solid content: 41% by mass) and 20.2 g of spherical aluminum powder A2-2 manufactured by Toyo Aluminum Powder Co., Ltd. (trade name: 08-0076, average particle) were added. Diameter: 6.8 μm, solid content: 99% by mass, average aspect ratio: 1), 43.3 g of a thermosetting urethane resin solution prepared by a synthesis example (solid content: 45 mass%), and 40 g of propylene glycol Methyl ether acetate was added, and 2.0 g of JER604 was added as a curing agent, and the mixture was stirred at 2000 rpm for 15 minutes using an ultrasonic homogenizer to obtain a discharge gap filling composition 2.

<Manufacture and evaluation of electrostatic discharge protectors> The discharge gap-filling composition 2 was used to obtain the electrostatic discharge protector C2 and the electrostatic discharge protector D2 by the above-described method, and the insulation, the actuation voltage, and the withstand voltage at the time of normal operation were evaluated. The results are shown in Table 1. [Example 3] <Modulation of composition for discharge gap filling>

48.8 g of the aluminum-containing powder paste A1-2 (solid content: 41% by mass), 5.1 g of the flaky aluminum powder A2-3 (trade name: 40, average particle diameter) 65 μm, solid content: 99% by mass, average aspect ratio: 10), 33.3 g of a thermosetting urethane resin solution prepared by a synthesis example (solid content: 45 mass%), and 45 g of triacetin 1.7 g of JER604 was added as a curing agent, and the mixture was stirred at 2000 rpm for 15 minutes using an ultrasonic homogenizer to obtain a discharge gap filling composition 3.

<Manufacture and evaluation of electrostatic discharge protectors>

The discharge gap-filling composition 3 was used to obtain the electrostatic discharge protector C3 and the electrostatic discharge protector D3 by the above-described method, and the insulation, the operating voltage, and the withstand voltage at the time of normal operation were evaluated. The results are shown in Table 1.

[Example 4] <Modulation of composition for discharge gap filling>

48.8 g of the aluminum-containing powder paste A1-2 (solid content: 41% by mass) and 13.2 g of flaky aluminum powder A2-4 manufactured by Showa Aluminum Powder Co., Ltd. (trade name: 552 N, average particle diameter: 24 μm, solid content: 65 mass%, average aspect ratio: 31), 37.8 g of a thermosetting urethane resin solution prepared by a synthesis example (solid content: 45 mass%), and 1.9 g of JER604 as a curing agent The mixture was stirred at 2000 rpm for 15 minutes using an ultrasonic homogenizer to obtain a discharge gap filling composition 4.

<Manufacture and evaluation of electrostatic discharge protectors>

The discharge gap filling composition 4 was used, and the electrostatic discharge protector C4 and the electrostatic discharge protector D4 were obtained by the above-described method, and the insulation, the operating voltage, and the withstand voltage at the time of normal operation were evaluated. The results are shown in Table 1.

[Example 5] <Modulation of composition for discharge gap filling>

48.8 g of the aluminum-containing powder paste A1-1 (solid content: 41% by mass) and 13.2 g of flaky aluminum powder A2-5 manufactured by Showa Aluminum Powder Co., Ltd. (trade name: 205 N, average particle diameter: 6 μm, solid content: 65 mass%, average aspect ratio: 17), 37.8 g of a thermosetting urethane resin solution prepared by a synthesis example (solid content: 45 mass%), and 1.9 g of JER604 as a curing agent The mixture was stirred at 2000 rpm for 15 minutes using an ultrasonic homogenizer to obtain a discharge gap filling composition 5.

<Manufacture and evaluation of electrostatic discharge protectors>

The discharge gap-filling composition 5 was used, and the electrostatic discharge protector C5 and the electrostatic discharge protector D5 were obtained by the above-described method, and the insulation, the operating voltage, and the withstand voltage at the time of normal operation were evaluated. The results are shown in Table 1.

[Embodiment 6] <Modulation of composition for discharge gap filling>

48.8 g of the aluminum-containing powder paste A1-1 (solid content: 41% by mass) and 13.2 g of flaky aluminum powder A2-6 manufactured by Showa Aluminum Powder Co., Ltd. (trade name: SL850, average particle diameter: 23 μm, solid content: 65 mass%, average aspect ratio: 28), 37.8 g of a thermosetting urethane resin solution prepared by a synthesis example (solid content: 45 mass%), and 1.9 g of JER604 as a curing agent The mixture was stirred at 2000 rpm for 15 minutes using an ultrasonic homogenizer to obtain a discharge gap filling composition 6.

<Manufacture and evaluation of electrostatic discharge protectors>

The discharge gap-filling composition 6 was used to obtain the electrostatic discharge protector C6 and the electrostatic discharge protector D6 by the above-described method, and the insulation, the operating voltage, and the withstand voltage at the time of normal operation were evaluated. The results are shown in Table 1.

[Embodiment 7] <Modulation of composition for discharge gap filling>

48.8 g of the aluminum-containing powder paste A1-1 (solid content: 41% by mass) and 13.2 g of flaky aluminum powder A2-7 manufactured by Showa Aluminum Powder Co., Ltd. (trade name: LB582, average particle diameter: 23 μm, solid content: 65 mass%, average aspect ratio: 9), 37.8 g of a thermosetting urethane resin solution prepared by a synthesis example (solid content: 45 mass%), and 1.9 g of JER604 as a curing agent The mixture was stirred at 2000 rpm for 15 minutes using an ultrasonic homogenizer to obtain a discharge gap filling composition 7.

<Manufacture and evaluation of electrostatic discharge protectors>

The discharge gap-filling composition 7 was used to obtain the electrostatic discharge protector C7 and the electrostatic discharge protector D7 by the above-described method, and the insulation, the operating voltage, and the withstand voltage at the time of normal operation were evaluated. The results are shown in Table 1.

[Comparative Example 1] <Modulation of composition for discharge gap filling>

No flaky aluminum powder (trade name: 576PS, average particle diameter: 20 μm, solid content: 65 mass%, average aspect ratio: 23) manufactured by Showa Aluminum Powder Co., Ltd. was used, and only 69.7 g of the aluminum-containing powder paste A1 was used. A discharge gap filling composition 8 was obtained in the same manner as in Example 1 except for the above.

<Manufacture and evaluation of electrostatic discharge protectors>

The composition 8 is filled with a discharge gap and static electricity is obtained by the aforementioned method. The discharge protector C8 and the electrostatic discharge protector D8 were used to evaluate the insulation, the operating voltage, and the withstand voltage at the time of normal operation. The results are shown in Table 1.

[Comparative Example 2] <Modulation of composition for discharge gap filling>

No aluminum powder paste A1-1 was added, and only 44.4 g of flaky aluminum powder A2-1 manufactured by Showa Aluminum Powder Co., Ltd. (trade name: 576 PS, average particle diameter: 20 μm, solid content: 65 mass%, average length) was used. A discharge gap filling composition 9 was obtained in the same manner as in Example 1 except that the width ratio: 23).

<Manufacture and evaluation of electrostatic discharge protectors>

The discharge gap-filling composition 9 was used, and the electrostatic discharge protector C9 and the electrostatic discharge protector D9 were obtained by the above-described method, and the insulation, the operating voltage, and the withstand voltage at the time of normal operation were evaluated. The results are shown in Table 1.

[Comparative Example 3] <Modulation of composition for discharge gap filling>

In place of the flaky shape, a nail-shaped nickel powder A2-8 (trade name: nickel powder #123, average particle diameter: 5 μm, solid content 99% by mass, average aspect ratio: 1) made of 17.2 g of NIKKO RICA (stock) was used. A discharge gap filling composition 10 was obtained in the same manner as in Example 1 except for the aluminum powder.

<Manufacture and evaluation of electrostatic discharge protectors>

The electrostatic discharge protector C10 and the electrostatic discharge protector D10 were obtained by the above-described method using the discharge gap-filling composition 10, and the insulation, the operating voltage, and the withstand voltage at the time of normal operation were evaluated. The results are shown in Table 1.

[Comparative Example 4] <Manufacture and evaluation of electrostatic discharge protectors>

The electrostatic discharge protector C11 and the electrostatic discharge protector D11 in which the discharge gap filling composition was not filled in the discharge gap were obtained, and the insulation, the operating voltage, and the withstand voltage at the time of normal operation were evaluated. The results are shown in Table 1.

The A1/A2 and (A1+A2)/binder components (B) in the table represent the mass ratio. Further, the binder component (B) contains a curing agent.

According to the results of Table 1, it is understood that the metal powder (A1) coated with the metal alkoxide hydrolyzed product on the surface of the metal-doped primary particles serves as a discharge gap-filling composition, and the insulation during general operation is maintained ( Reference Examples 1 to 7, Comparative Example 1, and Comparative Example 3). In the examples 1 to 7, the aluminum powder (A2) is mixed with the metal particles (A1) coated with the hydrolyzate of the metal alkoxide, and the electrostatic discharge protector having a discharge gap distance of 300 μm or more is also actuated. excellent In particular, in the first embodiment and the third to seventh embodiments, since the aluminum powder (A2) has a sheet shape, the actuation efficiency can be further improved and the operating voltage can be lowered. Further, in Example 1, Example 4, Example 6, and Example 7 in which the average particle diameter of the aluminum powder (A2) is in a more preferable range, the withstand voltage can be further imparted.

It can be seen that Comparative Example 1 and Comparative Example 3, which do not contain the aluminum powder (A2), have insulation properties during normal operation, but when the width of the discharge gap is 1 mm, the electrostatic discharge protector is not formed. In the case of Comparative Example 4, the same operating voltage was not effective. It is judged that, in Comparative Example 2, since the surface of the primary particle which does not contain a metal is covered with the metal powder (A1) which is infiltrated by the hydrolyzed product of the metal alkoxide, the insulation is not deteriorated in general operation, and the withstand voltage is remarkable. Degraded without functioning as an electrostatic discharge protector.

[Industrial availability]

A metal powder (A1) coated with a film composed of a metal alkoxide hydrolyzate, and a film not composed of a metal alkoxide hydrolyzed product, by using a surface of a primary particle containing a metal: The discharge gap filling composition of the coated aluminum powder (A2) and the binder component (B) can provide an electrostatic discharge protector which is low in cost, high in freedom, and excellent in workability.

Claims (19)

A discharge gap filling composition comprising a metal powder (A1), an aluminum powder (A2), and a binder component (B), wherein at least a part of a surface of the metal powder (A1)-based metal primary particle is When the film composed of the hydrolyzed product of the metal alkoxide is coated, the surface of the aluminum powder (A2)-based primary particles of aluminum is not covered by a film composed of a hydrolyzed product of a metal alkoxide. The composition for discharge gap filling according to the first aspect of the invention, wherein the shape of the primary particles of the metal of the metal powder (A1) and the shape of the primary particles of the aluminum powder (A2) are in the form of flakes. The composition for discharge gap filling according to item 1 or 2 of the patent application, wherein the average particle diameter of the primary particles of the metal of the metal powder (A1) is 1 to 15 μm, and the average of the primary particles of the aluminum powder (A2) The particle size is 5 to 70 μm. The discharge gap filling composition according to any one of the items 1 to 3, wherein the metal element of the metal powder (A1) is manganese, cerium, zirconium, hafnium, tantalum, molybdenum or vanadium. At least one selected from the group consisting of nickel, cobalt, chromium, magnesium, titanium or aluminum. The composition for discharge gap filling according to any one of the items 1 to 4, wherein the metal element of the metal of the metal powder (A1) is aluminum. The discharge gap filling composition according to any one of the items 1 to 5, wherein the metal powder in the discharge gap filling composition The mass ratio of the final (A1) to the aluminum powder (A2) is 98:2 to 20:80. The discharge gap filling composition according to any one of the items 1 to 6, wherein the metal alkoxide is represented by the following general formula (1). (In the formula (1), M is a metal atom, O is an oxygen atom, R is each independently an alkyl group having 1 to 20 carbon atoms, and n is an integer of 1 to 40). The composition for discharge gap filling according to claim 7, wherein M in the above general formula (1) is ruthenium, titanium, zirconium, hafnium or tantalum. The discharge gap filling composition according to any one of the first to eighth aspect, wherein the surface of the primary particles of the metal of the metal powder (A1) and/or the aluminum powder (A2) is auto-oxidized. membrane. The composition for discharge gap filling according to any one of the above-mentioned items, wherein the binder component (B) contains a thermosetting compound or an active energy ray-curable compound. The composition for discharge gap filling according to claim 10, wherein the binder component (B) contains a thermosetting urethane resin. Such as the discharge of any of the first to eleventh patent applications The composition for gap filling, wherein the total content of the metal powder (A1) and the metal powder (A2) in the solid content of the discharge gap filling composition is 3 to 95% by mass, and the content of the binder (B) is 5 ~97% by mass. An electrostatic discharge protector having at least two electrodes and an electrostatic discharge protector between the two electrodes, characterized in that it has any one of items 1 to 12 of the patent application scope The discharge gap filling composition of the item is filled in the discharge gap filling member formed by the discharge gap. The electrostatic discharge protector of claim 13, wherein the discharge gap has a width of 300 μm or more and 1 mm or less. The electrostatic discharge protector of claim 13 or 14, wherein a protective layer is formed on a surface of the discharge gap filling member. An electronic circuit board having an electrostatic discharge protector according to any one of claims 13 to 15. A flexible electronic circuit board having an electrostatic discharge protector according to any one of claims 13 to 15. An IC chip mounting substrate having an electrostatic discharge protector according to any one of claims 13 to 15. An electronic device comprising the electronic circuit board of claim 16 of the invention, the flexible electronic circuit board of claim 17 or the IC chip mounting substrate of claim 18 of the patent application.